environmental collapse

ARED DIAMOND likes his subjects big. His best-known book, “Guns, Germs and Steel”, was in some editions subtitled “A short history of everybody for the last 13,000 years”. This was no conventional history; rather, the author tried to explain the environmental factors behind the rise of various human civilisations. It was a terrific read and full of surprising subplots, such as why some animals can be domesticated and others cannot, and why agriculture spread to some societies but not others.

Now Mr Diamond, a professor of geography at the University of California, attempts to tackle the opposite question, that is, why some societies collapse. Again, he focuses on long-term environmental factors rather than on short-term political ones. Since Mr Diamond is a restless traveller, a ravenous researcher and a sparky writer, the result is gripping.

Among the collapses, he describes the civilisation of Easter Island three centuries ago, whose fall, he argues convincingly, was caused largely by deforestation. Transporting and erecting those extraordinary stone statues required a lot of wood. The early Easter Islanders also used wood to cook their food, cremate their dead and build large canoes. As the population grew, they cut down the big trees.

The ecosystem was wrecked. The soil was rendered infertile, and, with no big logs left with which to build seaworthy craft, the islanders had no means of escape. They could not even paddle far enough out to catch porpoises, which had been a chief source of protein. They ate their land birds to extinction and then they starved. Wars erupted, in which the victors ate the vanquished. A popular insult at the time, apparently, was: “The flesh of your mother sticks between my teeth.”